Blood storage bag system and depletion devices with oxygen and carbon dioxide depletion capabilities

ABSTRACT

A blood storage system. The system has a collection bag for red blood cells; an oxygen/carbon dioxide depletion device; a storage bag for red blood cells; and tubing connecting the collection bag to the depletion device and the depletion device to the storage bag. The depletion device includes a receptacle of a solid material having an inlet and an outlet adapted to receiving and expelling a flushing gas; a plurality of hollow fibers or gas-permeable films extending within the receptacle from an entrance to an exit thereof. The hollow fibers or gas-permeable films are adapted to receiving and conveying red blood cells.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 12/901,350, filed Oct. 8, 2010, now U.S. Pat. No.8,535,421, issued Sep. 17, 2013, which claims the benefit under 35U.S.C. §119(e) of U.S. Provisional Application No. 61/331,693, filed May5, 2010 and U.S. Provisional Application No. 61/250,661, filed Oct. 12,2009, all of which are hereby incorporated by reference in theirentireties.

BACKGROUND

1. Field

The present disclosure relates to a storage blood system having anoxygen/carbon dioxide depletion device and a blood storage bag for thelong-term storage of blood. More particularly, the present disclosurerelates to a blood storage system that is capable of removing oxygen andcarbon dioxide from the red blood prior to storage and during storage,as well as maintaining oxygen and/or carbon dioxide depleted statesduring storage, thereby prolonging the storage life and minimizingdeterioration of the deoxygenated red blood.

2. Background of the Art

Adequate blood supply and the storage thereof is a problem facing everymajor hospital and health organization around the world. Often, theamount of blood supply in storage is considerably smaller than the needtherefor. This is especially true during crisis periods such as naturalcatastrophes, war and the like, when the blood supply is oftenperilously close to running out. It is at critical times such as thesethat the cry for more donations of fresh blood is often heard. However,unfortunately, even when there is no crisis period, the blood supply andthat kept in storage must be constantly monitored and replenished,because stored blood does not maintain its viability for long.

Stored blood undergoes steady deterioration which is, in part, caused byhemoglobin oxidation and degradation and adenosine triphosphate (ATP)and 2-3,biphosphoglycerate (DPG) depletion. Oxygen causes hemoglobin(Hb) carried by the red blood cells (RBCs) to convert to met-Hb, thebreakdown of which produces toxic products such as hemichrome, hemin andfree Fe³⁺. Together with the oxygen, these products catalyze theformation of hydroxyl radicals (OH.cndot.), and both the OH.cndot. andthe met-Hb breakdown products damage the red blood cell lipid membrane,the membrane skeleton, and the cell contents. As such, stored blood isconsidered unusable after 6 weeks, as determined by the relativeinability of the red blood cells to survive in the circulation of thetransfusion recipient. The depletion of DPG prevents adequate transportof oxygen to tissue thereby lowering the efficacy of transfusionimmediately after administration (levels of DPG recover once inrecipient after 8-48 hrs). In addition, these deleterious effects alsoresult in reduced overall efficacy and increased side effects oftransfusion therapy with stored blood before expiration date, butpossibly older than two weeks are used. Reduction in carbon dioxidecontent in stored blood has the beneficial effect of elevating DPGlevels in red blood cells.

There is, therefore, a need to be able to deplete oxygen and carbondioxide levels in red blood cells prior to storage on a long-term basiswithout the stored blood undergoing the harmful effects caused by theoxygen and hemoglobin interaction. Furthermore, there is a need to storeoxygen and carbon dioxide depleted red blood cells in bags containing orbag surrounded by a barrier film with oxygen and carbon dioxidedepletion materials. Furthermore, there is a need to optimize ATP andDPG levels in stored red blood cells by varying the depletion orscavenging constituents prior to and/or during storage depending uponthe needs of the recipient upon transfusion. Furthermore, the bloodstorage devices and methods must be simple, inexpensive and capable oflong-term storage of the blood supply.

SUMMARY

A disposable device for blood storage that is able to deplete of oxygenand anaerobically store of red blood cells for transfusion.

The present disclosure also provides for a device and method of removingcarbon dioxide (CO₂) in addition to oxygen (O₂) prior to or at the onsetof anaerobic storage.

The present disclosure further provides for mixing O₂ and CO₂ scavengingmaterials that are placed in a depletion device to obtain optimal ATPand DPG levels.

The present disclosure also provides for a depletion device that has theability to scavenge CO₂ prior to or at the onset of anaerobic storage.

The present disclosure further provides for the anaerobic storage bagthat is capable of storing red blood cells anaerobically and in a CO₂depleted state.

The present disclosure provides for mixing of O₂ and CO₂ scavengingmaterials to be placed in a sachet or incorporated into the storage bagmaterials of construction within an anaerobic storage bag.

Accordingly, the present disclosure provides for a disposable device forblood storage that is able to deplete oxygen and carbon dioxide as wellas anaerobically store red blood cells for transfusion.

The present disclosure also provides for a system the anaerobic storageof RBCs with pre-storage oxygen and carbon dioxide depletion andcontinued maintenance of the anaerobic and carbon dioxide depleted stateduring storage.

The present disclosure further provides for the anaerobic storage ofstandard storage bags by storing them in a controlled-atmospherecontainer or chamber such as in an inert gas within a refrigerator.

The present disclosure provides for a blood collection system thatincorporates an oxygen/carbon dioxide depletion device having an oxygenand carbon dioxide sorbent in combination with a filter or membrane tostrip oxygen and carbon dioxide from the blood during transport to thestorage bag.

The present disclosure provides for a blood collection system theincorporates an oxygen/carbon dioxide depletion device that contains agas permeable film or membrane providing sufficient surface area tofacilitate diffusion of oxygen and carbon dioxide from the blood intothe interior of the device.

The present disclosure provides for a blood collection system thatincorporates an oxygen/carbon dioxide depletion device having an oxygenand carbon dioxide sorbent enclosed in gas permeable membrane with afilter or membrane to strip oxygen and carbon dioxide from the bloodduring transport to the storage bag.

The present disclosure also provides for a laminated storage bag forstoring red blood cells (RBCs). The storage bag may be a laminated baghaving an oxygen and carbon dioxide sorbent or a secondary bagcontaining an oxygen and carbon dioxide sorbent.

The present disclosure further provides for a system to deplete theoxygen and carbon dioxide from collected red blood cells that includesan additive solution, an oxygen and carbon dioxide depletion device, anda blood storage bag that maintains the red blood cells in an oxygen andcarbon dioxide depleted state.

The present disclosure provides for a system and methodology thatpermits reduction in carbon dioxide levels prior to storage and anincrease in DPG levels. By keeping carbon dioxide levels low, and, thus,DPG levels high, the affinity of oxygen to hemoglobin to bind oxygen isreduced. By having a lower affinity to hemoglobin, greater transmissionof oxygen to tissue is permitted.

The present disclosure provides for a method of optimizing ATP and DPGin red blood cells for storage by obtaining a sample of red blood cellsfrom a donor; depleting oxygen and carbon dioxide levels in the sampleto produce an oxygen and carbon dioxide depleted sample; storing theoxygen and carbon dioxide depleted sample in a container that maintainsoxygen and carbon dioxide depleted state of the sample. The range ofdepletion is variable.

The present disclosure also provides for optimizing stored blood bytreating the stored blood subject to a depletion device having theappropriate levels of oxygen and carbon dioxide gas passed therethroughor with the appropriate blend of oxygen and carbon dioxide depletingscavengers to obtain a desired level of constituents. The blood is alsostored under oxygen and or carbon dioxide depleted conditions.Immediately prior to transfusion, re-oxygenating of the stored blood asneeded based on the needs of the recipient prior to transfusion.

The present disclosure also provides another embodiment of a bloodstorage device. The device is a sealed receptacle adapted to retain andstore red blood cells. The receptacle has walls formed from a laminate.The laminate has (a) an outer layer of a material substantiallyimpermeable to oxygen and carbon dioxide, (b) an inner layer of amaterial compatible with red blood cells, and (c) an interstitial layerbetween the outer layer and the inner layer. The interstitial layer isof a material having admixed therein an amount of either or both of anoxygen scavenger and a carbon dioxide scavenger. Alternately, theinterstitial layer can be deleted and the scavenger(s) admixed into theinner and/or outer layer.

The present disclosure also provides another embodiment of a bloodstorage system. The system has a collection bag for red blood cells; aunitary device for depleting oxygen and carbon dioxide and reducingleukocytes and/or platelets from red blood cells; a storage bag for redblood cells; and tubing connecting the collection bag to the unitarydevice and the unitary device to the storage bag.

The present disclosure and its features and advantages will become moreapparent from the following detailed description with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the components of a disposable blood anaerobicstorage system of the present disclosure.

FIG. 2 illustrates a pre-storage oxygen/carbon dioxide depletion deviceof the present disclosure.

FIG. 3 illustrates a first embodiment of a blood storage bag having astorage bag with a secondary outer oxygen film containing an oxygensorbent in a pocket.

FIG. 4 a illustrates a pre-storage oxygen/carbon dioxide depletion baghaving a blood storage bag with a large sorbent sachet enclosed ingas-permeable, red blood cell compatible polymers in contact with theRBCs.

FIG. 4 b illustrates a third embodiment of a blood storage bag having astorage bag a laminated oxygen film barrier with a large sorbent incontact with the RBCs.

FIG. 5 a illustrates a fourth embodiment of a blood storage bag having asecondary configured secondary outer barrier bag surrounding an innerblood storage bag having an oxygen sorbent.

FIG. 5 b illustrates a fifth embodiment of a blood storage bag having asecondary outer barrier bag surrounding an inner blood storage baghaving a large oxygen sorbent sachet enclosed in a gas permeable, redblood cell compatible polymers in contact with RBCs.

FIGS. 6 a through 6 c illustrate an embodiment of a depletion devicethat depletes oxygen and carbon dioxide from red blood cells prior tostorage by a flushing inert gas or inert gas/CO₂ mixture of definedcomposition around a hollow fiber inside the assembly.

FIGS. 7 a through 7 c illustrate another embodiment of a depletiondevice that depletes oxygen and carbon dioxide from red blood cell priorto storage.

FIGS. 8 a through 8 c illustrate another embodiment of a depletiondevice that depletes oxygen and carbon dioxide from red blood cellsprior to storage wherein oxygen and/or CO₂ is scavenged by scavengermaterials in the core of the cylinder, surrounded by hollow fibers.

FIGS. 9 a through 9 c illustrate another embodiment of a depletiondevice that depletes oxygen and carbon dioxide from red blood cellsprior to storage wherein oxygen and/or CO₂ is scavenged by scavengermaterials surrounding cylinders of hollow fibers enveloped in gaspermeable, low water vapor transmission material.

FIG. 10 illustrates a plot of flow rate of RBC suspension per minuteversus oxygen partial pressure for the depletion devices of FIGS. 6 athrough 6 c, FIGS. 7 a through 7 c, FIGS. 8 a through 8 c and FIGS. 9 athrough 9 c.

FIGS. 11 a through 11 h illustrate plots of the effect of oxygen andoxygen and carbon dioxide depletion on metabolic status of red bloodcells during refrigerated storage.

FIG. 12 illustrates the components of another embodiment of a disposableblood anaerobic storage system of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings and in particular to FIG. 1, a disposableblood anaerobic storage system is shown and referenced using referencenumeral 10. The blood storage system includes an oxygen/carbon dioxidedepletion device 100 (OCDD 100), an anaerobic blood storage bag 200 andan additive solution bag 300 stored. OCDD 100 removes oxygen and carbondioxide from red blood cells traveling through it. The system alsocontains a leuko reduction filter 400. Components conventionallyassociated with the process of blood collection are a phlebotomy needle410, a blood collection bag 420 containing an anti-coagulant and a bag430 containing plasma. Tubing can connect the various components of theblood storage system 10 in various configurations (one embodimentshown). Tube 440 connects collection bag 420 with leuko reduction filter400. Tube 441 connects solution bag 300 with collection bag 420. Tube442 connects plasma bag 430 with collection bag 420. Tube 443 connectsleuko reduction filter 400 with OCDD 100. Tube 444 connects OCDD 100with blood storage bag 200. Blood storage system 10 is preferably asingle-use, disposable, low cost system.

Oxygen/carbon dioxide depletion device 100 removes the oxygen fromcollected RBCs prior to the RBCs being stored in blood storage bag 200.The oxygen content in RBCs must be depleted from oxy-hemoglobin becausemore than 99% of such oxygen is hemoglobin-bound in venous blood.Preferably, the degree of oxygen saturation is to be reduced to lessthan 4% within 48 hours of blood collection. The oxygen depletion ispreferably accomplished at room temperature. The affinity of oxygen tohemoglobin is highly dependent on the temperature, with a p50 of 26 mmHgat 37° C. dropping to ˜4 mmHg at 4° C. Furthermore, this increase in O₂affinity (Ka) is mainly due to reduction in O₂ release rate (k-off),resulting in an impractically low rate of oxygen removal once RBC iscooled to 4° C. Thus, it places a constraint on oxygen stripping suchthat it may be preferable to accomplish it before RBC are cooled tostorage temperatures of 1° C. to 6° C.

As an alternative or in addition to oxygen depletion, carbon dioxidedepletion has the beneficial effect of elevating DPG levels in red bloodcells. Carbon dioxide exists inside RBCs and in plasma in equilibriumwith HCO₃ ⁻ ion (carbonic acid). Carbon dioxide is mainly dissolved inRBC/plasma mixture as carbonic acid and rapid equilibrium between CO₂and carbonic acid is maintained by carbonic anhydrase inside RBC. Carbondioxide is freely permeable through RBC membrane, while HCO₃ ⁻ insideRBC and plasma is rapidly equilibrated by anion exchanger (band 3)protein. When CO₂ is removed from RBC suspension, it results in theknown alkalization of RBC interior and suspending medium. This resultsfrom removal of HCO₃ ⁻ inside and outside RBC; cytosolic HCO₃ ⁻ isconverted to CO₂ by carbonic anhydrase and removed, while plasma HCO₃ ⁻is removed via anion exchange inside RBC. Higher pH inside RBC is knownto enhance the rate of glycolysis and thereby increasing ATP and DPGlevels. ATP levels are higher in Ar/CO₂ (p<0.0001). DPG was maintainedbeyond 2 weeks in the Argon purged arm only (p<0.0001). Enhancedglycolysis rate is also predicted by dis-inhibition of key glycolyticenzymes via metabolic modulation and sequesterization of cytosolic-freeDPG upon deoxygenation of hemoglobin as a result of anaerobic condition.DPG was lost at the same rate in both control and Ar/CO₂ arms (p=0.6)despite thorough deoxygenation of hemoglobin, while very high levels ofATP were achieved with OFAS3 additive (FIGS. 11 a-d).

Referring to the drawings and in particular to FIG. 12, anotherembodiment of a disposable blood anaerobic storage system is shown andreferenced using reference numeral 500. The blood storage systemincludes a blood collection bag 510, an oxygen/carbon dioxide depletiondevice 535 (OCDD 535) and an anaerobic blood storage bag 528. OCDD 535removes oxygen and carbon dioxide from red blood cells traveling throughit. Tubing connects the various components of the blood storage system500. Tube 512 connects collection bag 510 with OCDD 535. Tubes 518 and520 connect OCDD 535 with blood storage bag 528. Blood storage system500 is preferably a single-use, disposable, low cost system.

Referring to FIG. 2, an oxygen/carbon dioxide depletion device (OCDD)101 contains an oxygen sorbent 110. OCDD 101 is a disposable cartridge105 containing oxygen sorbent 110 and a series of hollow fibers 115.Oxygen sorbent 110 is a mixture of non-toxic inorganic and/or organicsalts and ferrous iron or other materials with high reactivity towardoxygen. Oxygen sorbent 110 is made from particles that have significantabsorbing capacity for O₂ (more than 5 ml O₂/g) and can maintain theinside of cartridge 105 to less than 0.01% which corresponds to PO₂ lessthan 0.08 mmHg. Oxygen sorbent 110 is either free or contained in anoxygen permeable envelope. OCDD 101 of the present disclosure mustdeplete approximately 100 mL of oxygen from a unit of blood.

After oxygen and carbon dioxide have been stripped from RBCs in the OCDDof FIG. 2, RBCs are stored in a blood storage bag 200. The oxygencontent of RBC suspended in additive solution 300 must be reduced toequal to or less than 4% SO₂ before placing them in refrigeratedstorage. Further, oxygen depleted RBC must be kept in an anaerobic stateand low carbon dioxide state throughout entire storage duration.

RBCs pass through an oxygen permeable film or membrane 115. The membraneor films may be constructed in a flat sheet or hollow fiber form. Filmscan be non porous materials that are capable of high oxygen permeabilityrates (polyolefins, silicones, epoxies, polyesters etc) and membrane arehydrophobic porous structures. These may be constructed of polymers(polyolefins, Teflon, PVDF, polysulfone) or inorganic materials(ceramics). Oxygen depletion takes place as RBCs pass through membrane115. Hollow fibers may be used as a substitute for oxygen permeablefilms or membrane. OCDD provides a simple structure having a largesurface area to remove oxygen and maintain constant flow of bloodtherethrough. The oxygen depletion or removal is accomplished byirreversible reaction of ferrous ion in oxygen sorbent 110 with ambientoxygen to form ferric oxide. OCDD 101 does not need agitation for oxygenremoval and can be manufactured easily to withstand centrifugation aspart of a blood collection system as necessary.

Referring to FIGS. 6 a through 6 c and FIGS. 7 a through 7 c, examplesof flushing depletion devices are disclosed. The depletion devicesfunction to deplete, O₂ and CO₂, or O₂, or CO₂ alone, or O₂ withspecific levels of CO₂ by supplying appropriate composition of flushinggas. Gases appropriate for depletion devices are, for example, Ar, He,N₂, Ar/CO₂, or N₂/CO₂.

FIGS. 8 a through 8 c and 9 a through 9 c, also disclose scavengingdepletion devices. Depletion takes place with the use of scavengers orsorbents and without the use of external gases. In both types ofdepletion devices however, carbon dioxide depletion in conjunction withoxygen depletion is effective to enhance DPG and ATP, respectively,prior to storage in blood storage bags.

Referring to FIGS. 6 a through 6 c, a depletion device 20 is shown.Depletion device 20 includes a plurality of fibers 25, approximately5000 in number, through which red blood cells flow. Plurality of fibers25 are surrounded by a plastic cylinder 30. Plastic cylinder 30 containsa gas inlet 35 and a gas outlet 40 through which a flushing gas or acombination of flushing gases, such as those mentioned above, aresupplied to remove carbon and/or oxygen from blood. Specifications fordepletion device 20 are shown in Table 1 below.

TABLE 1 Prototype Eternal Gas External Gas Specification PathwaysPathways Prototype Serial #: Device 20 Fiber Type: Celgard 200/150-Celgard 66FPI 200/150-66FPI Number of Fibers: 5000 5000 Active Length of13 28 Fibers (cm): Fiber OD (microns): 200 200 Fiber ID (microns): 150150 Total Length of Fibers 15 30 Active Fiber Surface 0.4084 0.8796 Area(m2):

Referring to FIGS. 7 a through 7 c, a depletion device 45 is shown.Depletion device 45, like device 20 of FIGS. 6 a to 6 c, includes aplurality of fibers 50, approximately 5000 in number, through which redblood cells flow. Plurality of fibers 50 are surrounded by a plasticcylinder 55. Plastic cylinder 55 contains a gas inlet 60 and a gasoutlet 65 through which a gas or a combination of gases, such as thosementioned above are supplied to remove carbon dioxide and/or oxygen fromblood. Specifications for depletion device 45 are shown in Table 2below. The active surface area of depletion of device 45 is twice thatof device 20 because device 45 is twice as long as device 20.

TABLE 2 Prototype Eternal Gas External Gas Specification PathwaysPathways Prototype Serial #: Device 45 Fiber Type: Celgard 200/150-Celgard 66FPI 200/150-66FPI Number of Fibers: 5000 5000 Active Length of13 28 Fibers (cm): Fiber OD (microns): 200 200 Fiber ID (microns): 150150 Total Length of Fibers 15 30 Active Fiber Surface 0.4084 0.8796 Area(m2):

FIGS. 8 a through 8 c disclose a depletion device 70 having a core 75containing scavenging materials for either O₂, CO₂, or both O₂ and CO₂.Core 75 is packed by a gas permeable film with very low liquidpermeability. Hollow fibers 80 are wound around core 75, and a plasticcylinder 82 contains and envelopes hollow fibers 80. In this particularembodiment, the active surface area for depletion is approximately0.8796 m² as shown in Table 3 below.

TABLE 3 Prototype Center Core 10 individual Bundles Specification 125grams Sorbent 200 grams Sorbent Prototype Serial #: Device 70 FiberType: Celgard Celgard 200/150-66FPI 200/150-66FPI Number of Fibers: 50005000 Active Length of 13 28 Fibers (cm): Fiber OD 200 200 (microns):Fiber ID (microns): 150 150 Total Length of 15 30 Fibers Active Fiber0.8796 0.8796 Surface Area (m2):

FIGS. 9 a through 9 c disclose a depletion device 85 containing fiberbundles 87 enclosed in gas permeable film with very low liquidpermeability. Fiber bundles 87 are surrounded by scavenger materials 89for either O₂, CO₂ or both O₂ and CO₂. Fiber bundles 87 and scavengermaterials 89 are contained within a plastic cylinder 90. The activesurface area for depletion is approximately 0.8796 m² as shown in Table4 below.

TABLE 4 Prototype Center Core 10 individual Bundles Specification 125grams Sorbent 200 grams Sorbent Prototype Serial #: Device 85 FiberType: Celgard Celgard 200/150-66FPI 200/150-66FPI Number of Fibers: 50005000 Active Length of 13 28 Fibers (cm): Fiber OD (microns): 200 200Fiber ID (microns): 150 150 Total Length of 15 30 Fibers Active Fiber0.8796 0.8796 Surface Area (m²):

FIG. 10 is a plot of the performance of flushing depletion devices 20and 45 and scavenging depletion devices 70 and 85. The data of FIG. 10was plotted using the following conditions: Hematocrit, 62% (pooled 3units of pRBC), and 21° C. at various head heights to produce differentflow rates. Oxygen/carbon dioxide scavenger (Multisorb Technologies,Buffalo, N.Y.) was activated with adding 5% and 12% w/w water vapor fordevice 79 and device 85, respectively. Data are plotted with flow rate(g RBC suspension per min) vs. pO₂ (mmHg).

In the oxygen/carbon dioxide depletion devices disclosed herein, aplurality of gas permeable films/membranes may be substituted for theplurality of hollow fibers. The films and fibers may be packed in anysuitable configuration within the cartridge, such as linear orlongitudinal, spiral, or coil, so long as they can receive and conveyred blood cells.

FIG. 10 shows that lowest oxygen saturation is achieved using devices 45and 85. Device 45 exhibits a larger active surface area exposed to gasesalong length of fibers 50. Device 85 also has a long surface area ofexposure to scavenging materials. Device 85 has bundles 87 surrounded byscavenging materials 89. The space occupied by scavenging materials 89between bundles 87 promotes dispersion of oxygen and carbon dioxide fromred blood cells contained in fiber bundles 87, thus aiding scavenging ofoxygen and carbon dioxide from red blood cells.

A further use of the depletion devices is to add back oxygen and orcarbon dioxide prior to transfusion by flushing with pure oxygen or air.This use is for special cases, such as massive transfusions, where thecapacity of the lung to re-oxygenate transfused blood is not adequate,or sickle cell anemia.

Similarly, depletion devices can be used to obtain intermediate levelsor states of depletion of oxygen and carbon dioxide depending needs ofthe patient to obtain optimal levels in the transfused blood dependingupon the patients needs.

Referring to FIG. 3, a blood storage bag 200 according to a preferredembodiment of the present disclosure is provided. Blood bag 200 has aninner blood-compatible bag 250 (preferably polyvinyl chloride (PVC)),and an outer barrier film bag 255. The material of bag 250 is compatiblewith RBCs. Disposed between inner bag 250 and outer oxygen barrier filmbag 255 is a pocket that contains an oxygen/carbon dioxide sorbent 110.Barrier film bag 255 is laminated to the entire surface of inner bag250. Sorbent 110 is contained in a sachet 260, which is alternatelyreferred to as a pouch or pocket. Sorbent 110 is optimally locatedbetween tubing 440 that leads into and from bag 200, specificallybetween inner bag and outer oxygen barrier film bag 255. This locationwill ensure that oxygen disposed between these two bags will bescavenged or absorbed. Oxygen sorbent is ideally located in a pouch orpocket 260 and not in contact with RBCs. Oxygen sorbent may also becombined with CO₂ scavengers or sorbents, enabling sorbent 110 todeplete both oxygen and carbon dioxide at the same time.

Referring to FIGS. 4 a and 4 b, blood storage bags 201 and 202 areconfigured to store RBCs for extended storage periods of time. Innerblood storage bags 205 are preferably made from DEHP-plasticized PVC andare in contact with RBCs. DEHP-plasticized PVC is approximately 200 foldless permeable to oxygen compared to silicone. However, PVC isinsufficient as an oxygen barrier to maintain the anaerobic state ofRBCs throughout the storage duration. Therefore, blood storage bags 201and 202 are fabricated with outer transparent oxygen barrier film 206(e.g. nylon polymer) laminated to the outer surface inner blood bag 205.This approach, as well as one shown in FIG. 3, uses accepted PVC forblood contact surface (supplying DEHP for cell stabilization) at thesame time prevents oxygen entry into the bag during extended storage.

In FIG. 4 a, a small sachet 210 containing oxygen/carbon dioxide sorbent110 enveloped in oxygen-permeable, RBC compatible membrane is enclosedinside of laminated PVC bag 205 and in contact with RBCs. Small sachetenvelope 210 is preferably made from a silicone or siloxane materialwith high oxygen permeability of biocompatible material. Sachet envelope210 has a wall thickness of less than 0.13 mm thickness ensures that O₂permeability ceases to become the rate-limiting step. PVC bag 205 mayalso contain carbon dioxide scavengers.

Referring to FIG. 4 b, bag 202 has a similar configuration to bag 201 ofFIG. 4 a. However, bag 202 has a large sorbent 215 enclosed inside ofPVC bag 205. Large sorbent 215 preferably has a comb-like configurationto rapidly absorb oxygen during extended storage. The benefit oflaminated bags of FIGS. 4 a and 4 b is that once RBCs are anaerobicallystored in bags, no further special handling is required. Similarly, bag202 may contain carbon dioxide scavenger to provide carbondioxide-scavenging in addition to oxygen-scavenging capability.

Referring to the embodiments of FIGS. 5 a and 5 b, RBCs are stored insecondary bags 301 and 302, respectively, in order to maintain ananaerobic storage environment for RBC storage. Secondary bags 301 and302 are transparent oxygen barrier films (e.g., nylon polymer) thatcompensate for the inability of PVC blood bags 305 and 320,respectively, to operate as a sufficient oxygen barrier to maintain RBCsin an anaerobic state. Secondary bags 301 and 302 are made with anoxygen barrier film, preferably a nylon polymer or other transparent,flexible film with low oxygen permeability.

Referring to FIG. 5 a, a small oxygen/carbon dioxide sorbent 310 isdisposed between a PVC barrier bag 305 and secondary bag 306 to removeslowly diffusing oxygen. FIG. 5 a is similar to the preferred embodimentof the blood bag of FIG. 3 except that secondary bag 306 is separatefrom and not bonded to bag 305 in this embodiment. PVC bag 305 includingports are enclosed in secondary barrier bag 305. Oxygen sorbent 310 mayoptionally contain carbon dioxide scavengers to provide both oxygen andcarbon dioxide scavenging capability.

Referring to FIG. 5 b, a secondary bag 302 contains a large sachet 325inside of PVC bag 320. Sachet 325 is filled with oxygen/carbon dioxidesorbent 110. Sachet 325 is a molded element with surface texture toincrease the surface area. Sachet 325 has a comb-like geometry for rapidoxygen/carbon dioxide depletion. Sachet 325 acts rapidly to stripoxygen/carbon dioxide from RBCs prior to refrigeration and storage ofRBCs in place of OCDD of FIG. 2. However, with this configuration,agitation is necessary, therefore sachet 325 must possess a largesurface area, high oxygen/carbon dioxide permeability and mechanicalstrength to withstand centrifugation step during component preparationand the prolonged storage. Sachet 325 is preferably made from materialssuch as 0.15 mm thick silicone membrane with surface texture to increasethe surface area. Sachet 325 may be made from materials such as PTFE orother fluoropolymer. Sachet 325 may have a rectangular shape such, suchas, for example, a 4″×6″ rectangle, although other sizes are possible,for the anaerobic maintenance. Sachet 325 may contain carbon dioxidescavengers in addition to oxygen scavengers to provide oxygen and carbondioxide scavenging capability.

The embodiments of FIGS. 5 a and 5 b are easily made from off-shelfcomponents except for sachet 325 of FIG. 5 b. In order to access RBCsfor any testing, secondary bags 301 and 302 must be opened. Unless theunit is transfused within short time, RBC must be re-sealed with freshsorbent for further storage. (1 day air exposure of storage bag wouldnot oxygenate blood to appreciable degree, since PVC plasticized withDEHP has relatively low permeability to oxygen).

In FIGS. 4 a, 4 b, 5 a and 5 b, the PVC bag is preferably formed withthe oxygen barrier film, such as an SiO₂ layer formed with the sol-gelmethod. A portion of the sheet material will be sealed on standard heatsealing equipment, such as radiofrequency sealers. Materials options maybe obtained in extruded sheets and each tested for oxygen barrier,lamination integrity, and seal strength/integrity.

For each of the several embodiments addressed above, an additivesolution from bag 300 is provided prior to stripping oxygen and carbondioxide from the RBCs is used. The additive solution 300 preferablycontains the following composition adenine 2 mmol/L; glucose 110 mmol/L;mannitol 55 mmol/L; NaCl 26 mmol/L; Na₂HPO₄ 12 mmol/L citric acid and apH of 6.5. Additive solution 300 is preferably an acidic additivesolution OFAS3, although other similar additive solutions could also beused that are shown to enhance oxygen/carbon dioxide-depleted storage.OFAS3 has shown enhanced ATP levels and good in vivo recovery asdisclosed herein. While OFAS3 is a preferred additive solution, othersolutions that offer similar functionality could also be used.Alternatively, additive solutions used currently in the field, such asAS1, AS3, AS5, SAGM, and MAPS can also be used. Additive solutions helpto prevent rapid deterioration of RBCs during storage and are typicallyadded prior to RBCs being made anaerobic.

Additionally, we envision that the OCDD and storage bags 100 and 200 canbe manufactured independent of other components of the disposable,anaerobic blood storage system (i.e., every item upstream of andincluding leukoreduction filter 400 in FIG. 1).

It is within the scope of the present disclosure to remove oxygen fromthe RBCs or to strip oxygen and carbon dioxide from the blood prior tostorage in the storage bags. An oxygen scavenger can be used to removethe oxygen from the RBCs prior to storage in the blood bags. As usedherein, “oxygen scavenger” is a material that irreversibly binds to orcombines with oxygen under the conditions of use. For example, theoxygen can chemically react with some component of the material and beconverted into another compound. Any material where the off-rate ofbound oxygen is zero can serve as an oxygen scavenger. Examples ofoxygen scavengers include iron powders and organic compounds. The term“oxygen sorbent” may be used interchangeably herein with oxygenscavenger. As used herein, “carbon dioxide scavenger” is a material thatirreversibly binds to or combines with carbon dioxide under theconditions of use. For example, the carbon dioxide can chemically reactwith some component of the material and be converted into anothercompound. Any material where the off-rate of bound carbon dioxide iszero can serve as a carbon dioxide scavenger. The term “carbon dioxidesorbent” may be used interchangeably herein with carbon dioxidescavenger. For example, oxygen scavengers and carbon dioxide scavengersare provided by Multisorb Technologies (Buffalo, N.Y.). Oxygenscavengers may exhibit a secondary functionality of carbon dioxidescavenging. Such materials can be blended to a desired ratio to achievedesired results.

Carbon dioxide scavengers include metal oxides and metal hydroxides.Metal oxides react with water to produce metal hydroxides. The metalhydroxide reacts with carbon dioxide to form water and a metalcarbonate. For example, if calcium oxide is used, the calcium oxide willreact with water that is added to the sorbent to produce calciumhydroxideCaO+H₂O→Ca(OH)₂

The calcium hydroxide will react with carbon dioxide to form calciumcarbonate and water.Ca(OH)₂+CO₂→CaCO₃+H₂O

It will be appreciated that scavengers can be incorporated into storagereceptacles and bags in any known form, such as in sachets, patches,coatings, pockets, and packets.

If oxygen removal is completed prior to introduction of the RBCs to theblood storage device, then it can be accomplished by any method known inthe art. For example, a suspension of RBCs can be repeatedly flushedwith an inert gas (with or without a defined concentration of carbondioxide), with or without gentle mixing, until the desired oxygen and orcarbon dioxide content is reached or until substantially all of theoxygen and carbon dioxide has been removed. The inert gas can be argon,helium, nitrogen, mixtures thereof, or any other gas that does not bindto the hememoiety of hemoglobin.

The OCDDs and various storage bags of the present disclosure can be usedin varying combinations. For example, OCDD 101 of FIG. 2 can be usedwith blood bag of FIG. 3, 201 of FIG. 4 a or 301 of FIG. 5 a. Whenoxygen is depleted by in-bag sachet 215 of FIG. 5 b, it can be stored asin FIG. 5 b or oxygen/carbon dioxide-depleted content transferred to thefinal storage bag such as FIG. 3, FIG. 4 a or FIG. 5 a for extendedstorage. Other combinations and configurations are fully within thescope of the present disclosure.

The present disclosure also provides another embodiment of a bloodstorage device. The device is a sealed receptacle adapted to retain andstore red blood cells. The receptacle has walls formed from a laminate.The laminate has (a) an outer layer of a material substantiallyimpermeable to oxygen and carbon dioxide, (b) an inner layer of amaterial compatible with red blood cells, and (c) an interstitial layerbetween the outer layer and the inner layer. The interstitial layer isof a material having admixed therein an amount of either or both of anoxygen scavenger and a carbon dioxide scavenger. The layers preferablytake the form of polymers. A preferred polymer for the outer layer isnylon. A preferred polymer for inner layer is PVC. The polymer of theinterstitial layer should provide effective adhesion between the innerand outer layers and provide effective admixture of oxygen scavengersand/or carbon dioxide scavengers therein. Useful polymers for theinterstitial layer include, for example, olefin polymers, such asethylene and propylene homopolymers and copolymers, and acrylicpolymers.

The present disclosure also provides another embodiment of a bloodstorage system. The system has a collection bag for red blood cells; aunitary device for depleting oxygen and carbon dioxide and reducingleukocytes and/or platelets from red blood cells; a storage bag for redblood cells; and tubing connecting the collection bag to the unitarydevice and the unitary device to the storage bag. A feature of thisembodiment is that the functions of depleting oxygen and carbon dioxideand reducing leukocytes and/or platelets from red blood cells arecombined into a single, unitary device rather than require separatedevices. For instance, unitary device can take the form of a singlecartridge. Leukocyte and/or platelet reduction is typically carried outby passing red blood cells through a mesh. In this embodiment, a meshcan be incorporated into either the flushing or the scavengingoxygen/carbon dioxide depletion device disclosed herein. The mesh ispreferably located within the device so that leukocyte and/or plateletreduction takes place prior to the onset of flushing or scavenging.

The following are examples of the present disclosure and are not to beconstrued as limiting.

EXAMPLES

The eight graphs below show the results of a 3-arm study showing: acontrol (aerobic OFAS3 with no O₂ or CO₂ depletion), anaerobic OFAS3(both O₂ and CO₂ depleted with pure Ar), and O₂ only depleted with 95%Ar and 5% CO₂ (CO₂ is not depleted).

Whole blood was collected into CP2D (Pall), centrifuged 2K×G for 3minutes, plasma removed, and additive solution AS-3 (Nutricel, Pall), orexperimental OFAS3 added. The unit was evenly divided into 3 600 mLbags. 2 bags were gas exchanged ×7 with Ar or Ar/CO₂, transferred to 150mL PVC bags and stored 1° C. to 6° C. in anaerobic cylinders with Ar/H₂or Ar/H₂/CO₂. One control bag was treated in the same manner without agas exchange and stored 1° C. to 6° C. in ambient air. Bags were sampledweekly for up to 9 weeks.

The plots of FIGS. 11 a, 11 c, 11 e and 11 g: use the additive solutionOFAS3 (200 mL; experimental, proprietary) and the plots of FIGS. 11 b,11 d, 11 f and 11 h, use the AS-3 additive solution. Comparing additivesolutions, effects of CO₂ depletion on DPG levels were similar. OFAS3showed higher ATP when oxygen was depleted (±CO₂), and O₂ depletionalone showed significant enhancement of ATP compared to aerobic control.AS-3 additive exhibited no significant enhancement of ATP when O₂ alonewas depleted.

FIGS. 11 a and 11 b: DPG levels during storage. DPG levels weremaintained for over 2 weeks, when CO₂ was removed in addition to oxygen.

FIG. 11 c: ATP levels during storage with OFAS3. Highest ATP levels wereachieved with OFAS3 RBC when O₂ only was depleted. For O₂/CO₂ depletion,intermediate levels of ATP were observed compared to the control whilevery high DPG levels were attained during first 2.5 weeks. Very highlevels of ATP may suggest higher rate of 24-hour post transfusionrecovery. Therefore, extent of carbon dioxide and oxygen depletionlevels may be adjusted to meet the specific requirement of therecipient. DPG levels can be maintained very high (at the expense ofATP) for purposes of meeting acute oxygen demand of recipient.Conversely, very high ATP levels may allow higher 24-hour recovery rate(lower fraction of non-viable RBC upon transfusion) thereby reducing thequantity of blood needed to be transfused (up to 25% of RBC arenon-viable). More importantly, this would benefit chronically transfusedpatients who may not demand highest oxygen transport efficiencyimmediately after transfusion (DPG level recovers in body after 8-48hours) who suffers from toxic iron overloading caused by non-viableRBCs.

FIG. 11 d: ATP levels during storage with AS3. Highest ATP levels wereachieved with AS3 RBC when O₂ only was depleted. No significantdifferences in ATP levels where observed with control and O₂ depletionalone.

FIGS. 11 e and 11 f: pH of RBC cytosol (in) and suspending medium (ex).Immediately after gas exchange (day 0), significant rise in pH (in andex) was observed only when CO₂ was depleted together with O₂. Rapidrates of pH decline observed with CO₂/O₂ depleted samples were caused byhigher rates of lactate production (FIGS. 11 g and 11 h).

FIGS. 11 g and 11 h: Normalized (to hemoglobin) glucose and lactatelevels during storage with OFAS3 and AS3. Higher rates of glucosedepletion and lactate productions correspond to high DPG levels observedin panels A and B. Legends for symbols/lines are same for both panels.OFAS3 additive contains similar glucose concentration with ×2 volumeresulting in higher normalized glucose levels.

FIGS. 11 a and 11 c taken together, suggest that extent of increases(compared to control) of ATP and DPG levels may be adjusted bycontrolling level of CO₂ depletion, when O₂ is depleted. Higher glucoseutilization and lactate production were observed with enhanced DPGproduction (FIG. 11 g). This may be also effective with AS3 additive,since similar trend in glucose utilization and lactate production wereobserved (FIG. 11 h).

Although the present disclosure describes in detail certain embodiments,it is understood that variations and modifications exist known to thoseskilled in the art that are within the disclosure. Accordingly, thepresent disclosure is intended to encompass all such alternatives,modifications and variations that are within the scope of the disclosureas set forth in the disclosure.

What is claimed is:
 1. A method for removing oxygen from red bloodcells, comprising: passing red blood cells through an oxygen depletiondevice, wherein said depletion device comprises: a receptacle of a solidmaterial having an inlet and an outlet adapted to receiving andexpelling a flushing gas; and a plurality of gas-permeable films ormembranes extending within said receptacle from an entrance to an exitthereof, wherein said plurality of gas-permeable films or membranes areformed of a material permeable to oxygen and are adapted to receivingand conveying said red blood cells, wherein said plurality ofgas-permeable films or membranes are each constructed in a flat sheet,and wherein said flushing gas comprises 5% CO₂.
 2. The blood storagesystem comprising, a collection bag for red blood cells; an oxygendepletion device; an oxygen impermeable storage bag for red blood cells;and tubing connecting said collection bag to said oxygen depletiondevice and tubing connecting said oxygen depletion device to said oxygenimpermeable storage bag, wherein said oxygen depletion device comprises:a) a cartridge; a plurality of gas-permeable films or membranes formedof a material permeable to oxygen and are adapted to receiving andconveying red blood cells extending within said cartridge from anentrance to an exit thereof; and an amount of an oxygen scavenger packedwithin said cartridge and contiguous to and in between said plurality ofgas-permeable films or membranes; or, b) a receptacle of a solidmaterial having an inlet and an outlet adapted to receiving andexpelling a flushing gas; and a plurality of gas-permeable films ormembranes formed of a material permeable to oxygen and are adapted toreceiving and conveying red blood cells extending within said receptaclefrom an entrance to an exit thereof, wherein said plurality ofgas-permeable films or membranes are each constructed in a flat sheet,and wherein said oxygen impermeable storage bag for red blood cells hasan inner blood-compatible surface comprising di-2-ethylhexyl phthalate(DEHP) plasticized polyvinyl-chlorine (PVC).
 3. A blood storage systemcomprising: a collection bag for red blood cells; a unitary device fordepleting oxygen and reducing leukocytes from red blood cells; an oxygenimpermeable storage bag for red blood cells; and tubing connecting thecollection bag to said unitary device and tubing connecting said unitarydevice to said oxygen impermeable storage bag.
 4. The blood storagesystem of claim 3, wherein said unitary device further comprisesplatelet depletion.
 5. The blood storage system of claim 3, wherein saidoxygen impermeable storage bag for red blood cells has an innerblood-compatible surface comprising di-2-ethylhexyl phthalate (DEHP)plasticized polyvinyl-chlorine (PVC).
 6. The blood storage system ofclaim 3, wherein said oxygen impermeable storage bag for red blood cellshas an inner blood-compatible surface without di-2-ethylhexyl phthalate(DEHP).
 7. A method for increasing adenosine triphosphate (ATP) levelsin red blood cells, comprising: mixing red blood cells with an acidicadditive solution, and passing said red blood cells through an oxygendepletion device, wherein said oxygen depletion device comprises: a) acartridge; a plurality of gas-permeable films or membranes, extendingwithin said cartridge from an entrance to an exit thereof, formed of amaterial permeable to oxygen and adapted to receiving and conveying saidred blood cells; and an amount of an oxygen scavenger packed within saidcartridge and contiguous to and in between said plurality ofgas-permeable films or membranes; or, b) a receptacle of a solidmaterial having an inlet and an outlet adapted to receiving andexpelling a flushing gas; and a plurality of gas-permeable films ormembranes formed of a material permeable to oxygen and are adapted toreceiving and conveying said red blood cells extending within saidreceptacle from an entrance to an exit thereof, wherein said pluralityof gas-permeable films or membranes are each constructed in a flatsheet.
 8. The method of claim 7, wherein said oxygen depletion devicedepletes oxygen in said red blood cells to less than, or equal to, 4%oxygen saturation (SO₂).